1. Field Of The Invention
This invention relates to fiberglass reinforced plastic ("FRP") window sash frames, and more particularly to window sash framing members which are formed by joining subframing members associated with the framing members.
2. Description Of The Related Art
Window sash frames made of synthetic resinous materials are known. These frames are composed of framing members, known as rails (horizontal members) and stiles (vertical members) formed by extrusions and composed of vinyl, for example. These types of window frames serve to provide the desired thermal insulation while establishing other desired performance characteristics such as elimination of the need for painting and resistance to chipping, scratching and other aesthetically unpleasant changes in the article. See U.S. Pat. Nos. 4,428,156, 4,676,026 and 4,689,933.
The separate framing members may be joined at a corner mitre joint. This corner mitre joint can be effected by welding, a screw connection, cementing or by using additional connecting members insertable in the frame. See U.S. Pat. Nos. 4,370,830 and 4,624,091.
It is known to provide these frames with aluminum reinforcing members. These reinforcing members stiffen the framing members and fill recesses created in the framing member profile See U.S. Pat. No. 4,624,091.
U.S. Pat. No. 4,753,043 discloses a glass door. The door consists of a structural frame having top and bottom tubular members and side tubular members. These members are coupled by corner keys which have a pair of perpendicularly disposed legs adapted for insertion into abutting ends of the members. The members are then secured to the corner key legs by rivets.
It is also known to have sashes made of hollow vinyl sash members which are mitred on each end. Aluminum reinforcement bars are inserted in the hollow area of the vinyl sash frame members. Typically, the top and bottom aluminum reinforcement bars are cut short of butting against the two side aluminum reinforcement bars. Screws are inserted through the vinyl sash frame members and aluminum bars of both ends of two of the four vinyl window sash framing members.
Despite the above products, there remains a need for a FRP window sash frame that has framing members which are tightly joined without the use of anchoring holes in the FRP framing members.